


To The Gills

by Shinsun



Category: Kuroko no Basuke | Kuroko's Basketball
Genre: M/M, Spawning, Teratophilia, Underwater Blowjobs, a fresh(water) take on this trope, and graphic descriptions of fins and gills, and lots of water technicalities, author is a marine bio nerd and an aquarist, eat your heart out Del Toro, getting that fish dick™, gill touching, handjobs, if Aomine is in water in this please assume it's dechlorinated, jacuzzi sex, merman au, no Finding Dory logic in this house, so expect some (mostly) anatomically-correct fish sex, the smut doesn't happen until like page 15, there's a lot of set up
Language: English
Status: Completed
Published: 2020-03-01
Updated: 2020-03-01
Packaged: 2021-02-28 05:35:58
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 9,440
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22964761
Author URL: https://archiveofourown.org/users/Shinsun/pseuds/Shinsun
Summary: “Are you… I mean… are you a for-real mermaid?”Aomine snorts, “A mermaid, seriously?”“What else would you call a creature that’s half human, half fish?” Taiga asks defensively.“I’m nothalfanything."--While on summer vacation at his father’s lakehouse, Kagami Taiga comes across an unusual creature stranded in the lake by a storm. Bringing him in and helping to treat his injuries leads to some unexpected developments.
Relationships: Aomine Daiki/Kagami Taiga
Comments: 10
Kudos: 144





	To The Gills

A summer storm wrecks the marshland within the first week of Taiga’s vacation. In the night, he can hear the roaring of the wind and the hammer of vicious rain against the windows, thunder crashing through the distant trees that surround his father’s lakehouse. There’s usually something soothing about the sound of a storm when he’s tucked safe inside, but out here in the middle of nowhere, it actually feels a little creepy. Besides, he can’t help thinking about the new patio furniture outside, and how he’ll probably be the one tasked with cleaning it in the morning.

It’s been unusually dry this year, with hardly a drop of rain since spring, and maybe this is nature’s personal way of making up for it, or maybe it’s just an individual “fuck you” to Taiga and his plans to sit around with the new video game Tatsuya sent and ignore all the uncivilized greenery outside. His father bought this lakehouse -- really, more of a marsh house, but the water’s deep enough for boats and that’s apparently enough for him -- way out here in the boonies with the claim that the quiet of nature would be an escape, but the monster LED flatscreen in the living room tells a bit of a different tale, as does the premium outdoor jacuzzi two meters from the lake.

Come to think of it, Taiga will probably be roped into cleaning swamp gunk out of _that_ , too. So much for his vacation. 

The rain does stop by morning, the sun peeling through Taiga’s window through a curtain of water drops pattering from the gutters outside. The sky is aggressively blue and cloudless now, like it’s never had a storm in its life, and as he peers over the window ledge to glimpse the lake below, Taiga is surprised to find that not only has it swollen far beyond its banks, it’s been completely trashed. Jagged branches are sticking up all over it, ripped from their respective trees; the dock on the opposite shore is practically underwater, and the little rowboat that’s always moored at it is untethered and flipped upside down a good distance away. 

Forget _cleaning_ the patio furniture, he’s probably going to have to fish it out of the goddamn lake in hip waders. Or scuba gear.

He doesn’t have either of those on hand, though, so, before his dad can even finish asking, he puts on his swim trunks and thick rubber boots and heads out into the wreckage. Best to just get it over with quickly, he figures.

The water comes almost all the way to the front door, dark with mud and who knows what else, and as he splashes across the patio, Taiga finds himself thinking they’re pretty lucky the storm hadn’t knocked down a power line, or tore the shutters off the windows. 

It’s up to his knees by the time he reaches the bank of the actual lake, now completely submerged, the squashy marsh bottom causing his boots to sink a little as he forges ahead. The sprawl of fallen, leafy debris on either side makes him feel like he’s crossing through the Amazon, but there’s still no sign of the patio furniture. 

He almost falls ass-first in the water when a hoarse shout and a splash breaks the quiet, his heart jumping into overdrive.

“Hey! Over here!”

The nearest village is all the way up the road and around the mountains from here, and even if it were closer, there’s no reason someone should be this near the lakehouse now that it’s become such a massive flood zone. But that voice had sounded desperate; maybe someone got stranded in the storm and is looking for help. And so, fighting down his initial surge of panic, Taiga turns in the direction of the noise, pushing aside an obstruction of branches in his way. 

One of his father’s chaise deck chairs is sticking out of the shallow water, its frame splintered and tipped on its side. And tangled in the plastic straps of it, he glimpses an arm, a shoulder, a distraught, frustrated face --

“Are you just gonna stand there?” the same voice demands.

Taiga splashes quickly over to the upended chair, resigned to help whatever dumbass managed to get his arms stuck in it, but he stops in his soggy tracks as he gets closer and glimpses the rest of the person’s body, twisted in the broken slatted mess trailing out of the murky water.

There isn’t a clear divide; the lower part of the man’s stomach smoothly transitions from skin to scales, darker ones like deep blue stones creeping up around the long fin that starts between his straining shoulder blades. About halfway down the stalk of his tail -- because that sure as fuck is a tail; a wide, vertical spade shape shot through with pale blue rays and ending in a ragged, bloody edge -- is another, smaller fin, and beside that is a long, straight gash, oozing blood into the lake.

“What the --?” Taiga can’t manage any more than that, and then the man -- the _creature_ , really _\--_ thrashes his injured tail and glares at him pointedly with intense, almost black eyes. Taiga only realizes in that moment that his chest is heaving, his mouth open and gasping uselessly for air, because those must surely be gills curving around his ribs, just below his immobilized arms.

“Shit, okay,” he says, shaking off the absurdity of what he’s seeing and reaching through the slats to untangle the creature’s hands.

As soon he gets one free, it immediately starts working to help free the other, and then both go for the straps imprisoning his tail. He doesn’t get that far, though, because without the straps suspending his torso, he falls back headfirst into the water, his face briefly disappearing below the surface.

Taiga stares, frozen, at the space where it used to be. A second later, with a clench of his powerful abdomen, the creature reappears, spitting lake water but seeming to have caught a proper breath while he was under.

“For fuck’s sake,” he scowls, with a frustrated wiggle of his tail. There are still two straps twisted around it, and it’s still bleeding pretty profusely, and that’s enough to push Taiga to unravel the rest of the snare. One last wrench of his scaly, sinewy body, and the creature struggles free.

Half of Taiga expects him to vanish under the water and swim away with no further ado, and he’ll just grab what remains of his dad’s broken patio furniture and spend the rest of his life wondering if he imagined the whole thing. And it seems like the thought crosses the creature’s mind too, but he hesitates, brow furrowed over those dark, unblinking eyes as he seems to struggle with something.

“Thanks,” he says at last, rather sulkily, crossing his arms underwater and averting his gaze. 

Taiga blinks, and squats a little to bring himself eye-level with him, barely able to glimpse the filaments of his gossamer blue fins below the surface.

“What’s your name?”

The dark eyes return to his, and the creature frowns. “Aomine.” He cocks his head in a nonverbal return of the question.

“Kagami,” Taiga says, without thinking. “Aomine, are you… I mean… are you a for-real mermaid?”

Aomine snorts, “A mermaid, seriously?”

“What else would you call a creature that’s half human, half fish?” Taiga asks defensively. 

“I’m not _half_ anything,” Aomine says, with an offended flick of his tail beside him, “You’re not from around here, are you?”

“...You’re bleeding, you know,” Taiga points out, in lieu of answering, indicated the red, tattered edge of his tail.

Aomine’s gaze turns for the first time to his injuries, and he grimaces.

“Yeah, I know. Gonna make it a real bitch to swim back up the channel. Fucking storm dumped me in this mudhole and I hit some kind of… glass circle?”

Taiga winces, “Uh yeah, that’s… that was my dad’s patio table. That’s what cut you?”

“Probably. That and about a million broken twigs.”

“Let me help,” Taiga blurts, a twist of guilt pulling the words out unbidden. Aomine stares at him. “Um, I’ve got -- I mean -- bandages? Medicine?”

“My family will have medicine,” Aomine points out bluntly, shaking his head. “Thanks again for getting me loose, but I’ve got it from here.”

He turns toward the middle of the lake, dragging his arms through the water, but he only manages about four weak strokes, his tail jerking like a broken rudder, before he stops with a gasp of pain, listing over to one side.

“Shit,” he pants, treading in place using only his arms.

“Dude, seriously,” Taiga says, sloshing through the deeper water after him. “You’ll make it _worse_ , you shouldn’t try swimming anywhere right now. Also, this water’s like… disgusting, you could end up with an infection or something.”

“Well then I can’t _stay_ here, can I?” Aomine retorts, facing him with a small splash. “What’s your brilliant solution?”

“Uh,” Taiga says, thinking fast. “I could... ask my dad?”

Aomine doesn’t look thrilled by this idea, and honestly, Taiga’s not either, but for all that he could say about his father, he is good in a crisis. And Taiga is pretty sure this counts as a crisis.

He brings Aomine about as far as the patio before the water gets too shallow to cover his gills. He knows this because Aomine tells him so, pulling his arm from Taiga’s grasp and refusing to be led any further. 

He’s laying on his belly in the same spot, his arms folded on the bottom step of the patio with his head propped up on them, when Taiga finally convinces his father to come outside. Taiga is relieved he’s still there, not just because he hadn’t put him past trying to swim off again once he was left alone, but because a part of his brain is still half-convinced that if he turns his back on Aomine, he won’t be real. He never will have been.

The real test, he supposes, will be if his father can see him too.

“Alright,” his father is saying, pulling work gloves over his hands as he follows him across the skin of water covering the patio, “Let’s see the damage. And don’t tell me you got cut trying to move any of that broken glass.”

“I didn’t,” Taiga says over his shoulder, “but someone else did.”

“Ah, shit,” his father sighs, breaking off as they come to the edge of the stairs. 

Aomine’s tail and gills aren’t visible from here, but it’d be hard to miss the prominent ridge of his dorsal fin, or the swathe of slate blue scales along his exposed back. He lifts his head and looks at Taiga’s father with no discernible expression, and it occurs to Taiga that he still hasn’t seen him blink once. Occurs to Taiga that maybe he just doesn’t.

“Dad,” he says, as the silence drags out. “This is Aomine.”

“My God…” his father says, after a moment. “I -- I didn’t think they were real.”

“And there it is,” Aomine quips, swishing his tail through the water and raising tiny waves on the surface.

“What do you mean?” Taiga asks, turning to his father. 

“There’s a legend,” his father says, “in the village, about the creatures that live on this island. Creatures that swim in the mountain streams and deepwater paddies, and tend to the rice fields in exchange for food and gifts. They’re supposed to be good luck.”

“Is that true?” Taiga asks Aomine, thrown.

Aomine shrugs, “I mean -- some of it? The rice thing’s not so common anymore, and I think the good luck thing’s always been bullshit. Something to deter poachers, I guess.”

“Huh,” Taiga says, crouching down at the edge of the stairs. His father joins him there shortly, copying his position.

“So are you the one who’s been cut by broken glass?” he asks. He seems to be having a bit of a hard time keeping his eyes on Aomine’s face.

As an answer, Aomine turns onto his side and lifts his tail out of the water, grunting with the effort. The gash in his scaly skin is bleeding slower now, after soaking in the cold water, but its edges are raw and angry red, and now that Taiga is seeing it up close, it looks deep.

His father hisses a breath between his teeth, “I won’t lie, it looks pretty bad. And I doubt the floodwater is doing you any favors as far as staving off infection.”

“That’s what I said,” Taiga offers, earning him a petulant glare from Aomine. “What should we do?”

“I’m no expert,” his father says slowly, “but I’d imagine submerging it in clean, treated water for awhile would be a start. Maybe an antibiotic or saline solution… though I’m not sure if salt would hurt a freshwater fish.”

“It won’t,” Aomine says, lowering his tail back into the water, and he doesn’t object to being called a fish, though Taiga had expected him to. Maybe he’s trying to stay in Taiga’s dad’s good graces as long as he’s offering to help. “But where am I supposed to go that has that much clean water?”

Taiga sees his dad’s gaze shift to the jacuzzi at the edge of the patio and back, thoughtful.

“Would that work?” Taiga asks, seized by the possibility. “Isn’t it chlorinated, though? And full of mud and leaves?”

“We’d have to clean and drain it, of course,” his father says, getting to his feet. “But it’s big enough, and everything from the temperature to the flow rate is adjustable; if we could treat that much water, it would probably be just the thing.”

“What are you talking about?” Aomine demands, bracing his hands on the step in front of him in order to lean forward. His face looks wary, anxious and expectant.

“In the meantime, though,” Taiga’s father continues, as if he hadn’t heard. “We’d have to come up with a simpler workaround...”

“The bathtub?” Taiga suggests, off the top of his head.

“I _said_ \--” Aomine insists, before he’s cut off.

“How would you feel about staying in a bathtub?” Taiga’s dad asks him. “Temporarily, of course; for a day at the most. It’d be small, but we should have enough distilled water to --”

“Um,” Aomine says, narrowing his eyes. “How small are we talking here?”

“What would you say our bathtub is, Taiga? Two hundred liters? Three?”

“No idea,” Taiga says, at the same time that Aomine says, “Liters?”

“Ah… right,” his father says, and Taiga can almost see the calculations scrolling through his head. “Well, I suppose your other option is to remain in the lake and hope you don’t lose your tail to gangrene...”

The glance Aomine throws at the aforementioned limb is panicked, but the fear doesn’t make it into his voice as he turns back around.

“I’ll do it,” he says. “The bathtub thing. I mean, how bad could it be?”

.

.

“This is the worst thing that’s ever happened to me.”

“Don’t be so dramatic,” Taiga says, sitting on the tile floor beside the bathtub, setting a plate in his lap, and another on the rim. “Here, I brought you some food.”

“‘ _Small’_ doesn’t cover it,” Aomine says, without even looking at the offering, “it’s titchy, it’s miniscule, I can’t even turn around without folding myself in half.”

“Your tail’s looking better, though,” Taiga offers helpfully, raising a bite of grilled mackerel and rice to his own lips.

Aomine sighs, and sinks into the water until his chin is below the surface, his tail displaced and curling over the ceramic.

“I’m going to die alone in a bathtub,” he mutters in a voice of pure defeat.

“Not alone,” Taiga corrects him, scooting closer. “And you’re not gonna die, you’re gonna be fine. You should eat, though, before it gets cold.”

Aomine glances at the plate on the edge of the tub, and heaves a reluctant sigh, pushing himself up and moving his tail to the side. The water is so much clearer than the lake that Taiga can see everything; the translucent film of the fins on his body, the dark lateral line along the length of it where his scales turn deepest blue, the ones on his underside seeming softer and more pastel, faded almost gray against his skin. He can even watch his gills working, though they remain submerged in this new position. Long, dusky slits that arc around his sides, and open and close rhythmically as he sniffs at the food on the plate, showing occasional flashes of delicate tissue inside. 

“You can breathe through your nose?” Taiga asks abruptly, just as Aomine stops inspecting the chunks of fish and starts to pick one up between his fingers.

“Sure,” Aomine says. “I have to, sometimes, but it’s more of a backup system than anything else. Makes deep water swimming risky, though… if I stay under too long, I can drown. Just like you.”

“So the ocean’s pretty off limits for you, huh?”

Aomine laughs, selects his piece of mackerel, and sits back. 

“You have no idea. A little salt dip like this is probably fine, but being in seawater could kill me.”

“No kidding?” Taiga says, setting down his chopsticks. Aomine nods and pops the mackerel into his mouth, his eyes going wide just before he swallows.

“Damn, that’s good,” he says, grabbing another piece. “Where’d you get this?”

“I made it,” Taiga says. “I wasn’t sure what you’d eat, but I figured seafood might be a safe bet.”

“Yeah, sometimes the village people will share what they catch, but never anything this tasty.”

Taiga hums thoughtfully and picks up his chopsticks again, watching Aomine devour the remaining pieces on his plate with gusto, his earlier despair apparently forgotten.

“Speaking of,” he says when he’s finished, licking fish oil from this thumb. “They always said in the village that no one lived in this marsh house. I thought it was abandoned.”

“My dad bought it last year,” Taiga explains, after taking a bite of his own food. “I’m just here for the summer, though, while school is out.”

“School?” 

Taiga can’t help but smirk at his confused tone, “An institute of education. You telling me _fish_ people don’t go to school?”

“Very funny,” Aomine says, giving his tail an annoyed flick. “I do have my studies, but they aren’t exactly seasonal.”

“Do you have homework?”

Aomine rolls his eyes, “My people are nomadic, Kagami. We don’t have homes.”

Taiga blinks, not least because he hadn’t really expected that Aomine would remember his name, considering the circumstances in which he’d given it to him.

He opens his mouth to respond, but before he can, there’s a knock on the bathroom door.

“Come on in, Dad,” Taiga says, raising his voice. 

The door swings open, and his father steps inside, holding his phone in one hand. 

“Alright boys, I have good news and bad news,” he announces, stowing the device in his pocket.

Taiga thinks Aomine might be a bit startled to be included in ‘ _boys’_ , because his spine stiffens considerably as he says, “Good news first.”

“Okay, the good news is the spa has been emptied, and I found a place in town that carries a strong enough water conditioner to fill it back up completely. The bad news is, the road is closed due to flooding, and won’t be open again until tomorrow.” 

“Shit,” Taiga says.

“So I’m stuck here all night?” Aomine exclaims, moving his tail with a splash. “You said _one_ day!”

“I’m sorry,” Taiga’s father says. “I’m afraid you’ll have to hold on a little longer.”

“It’s okay,” Taiga adds. “You seem to be doing fine, I’m sure one night won’t kill you.”

“Easy for you to say,” Aomine says. “What if my tail gets paralyzed from being bent in half all night? Besides, there’s no circulation in here, and distilled water is hell on my slime coat --”

“Your what?” Taiga says, before his father interrupts him.

“First thing in the morning, we’ll get it set up; I should have it ready to go and be able to move you no later than noon. ...If you really can’t wait that long, though, we can release you back into the lake tonight. I won’t hold you hostage if you’re that unwilling.”

Aomine hesitates, a flash of conflict crossing his face. Under the water, Taiga can see his gill slits moving faster; the only outward sign that he might be afraid.

“It’s fine,” he says at last, slumping into the bathtub and sloshing water over the side. “I’ll manage.”

“Are you sure?” Taiga asks, leaning closer to read the resignation and stress on his face.

“Yeah,” Aomine says. “I think so.”

  
  


.

.

In the middle of the night, Taiga gets up to take a piss. He’s been sharing the bathroom in his father’s room for most of the day since the other became occupied, but he doesn’t particularly want to wake him now, and that also gives him an excuse to see how Aomine is holding up.

He opens the door as quietly as he can, barely able to make out the reflections on the water in the darkened room.

“Hey,” he whispers into the blackness. “Are you awake?”

“Yeah,” Aomine says softly, over a muted splash of movement. “Can’t sleep. You can come in if you want.”

“Can I turn on the light?”

“Sure.”

Lifting the dimmer switch, Taiga watches Aomine come into focus, lying on his back in the bathtub with his face just above the surface, his tail tucked to one side.

“You doing okay?”

Aomine hums in a way that sounds vaguely affirmative, looking at the ceiling.

“Bored, mostly.”

“Well, I can stay awhile and entertain you if you want,” Taiga shrugs. “Do you mind if I take a leak first?”

“Go ahead.”

“Want me to close the shower curtain?”

Aomine snorts a laugh, “If you think I haven’t seen a human dick before, I’ve got some bad news for you.”

“Okay then,” Taiga shrugs, but as he lowers his pants and lifts the toilet seat, Aomine seems to be deliberately averting his eyes. And he doesn’t speak until Taiga finishes his business and flushes.

“Your dad had better be right about getting me out of here tomorrow,” is what he finally says, still looking away.

After washing his hands, Taiga comes to sit beside the tub, crossing one leg over the other, “I don’t think he’d say it if he didn’t believe it. Why, is it really that bad?”

Aomine shifts with an uncomfortable grunt, his tail stretching briefly out of the water to its full length, before he curls it around to his other side.

“Keeps cramping up,” he complains, “I know moving around too much won’t help it heal, but I don’t think keeping it still is helping either. And besides that... I don’t really have the liberty of flushing things away.”

“Oh,” Taiga says, wrinkling his nose sympathetically. “Well, the jacuzzi has a filter, and jets that move the water around. That’ll probably help things a lot.”

“And it’s outside,” Aomine adds, sounding almost wistful. “It’s weird being in here and not being able to see the stars.”

Crossing his arms on the rim of the tub, Taiga rests his chin on them and peers down at his face, “Where do you usually sleep? I assumed it’d be a cave or something.”

“Nah, that wouldn’t be very comfortable... or safe, really. I’ll usually sleep in pools by the marsh; the water is calmest there, and the grass is soft.”

“Out in the open? What about wild animals?”

“Oh, I’ll see them coming,” Aomine says lightly, and as Taiga watches, a flicker of movement sweeps across his dark eyes; a brief flash of thin transparent lenses. 

Which probably explains why he doesn’t need to blink. In the split-second that his clear eyelids lifted, though, Taiga thinks that his eyes might’ve been brighter, bluer. It could have been his imagination.

“...Tell me something, Kagami,” he says after a moment, folding his arms behind his head.

“Hm?”

“Why’re you helping me? I mean, why go to all this trouble?”

“Well, my dad’s the one who --” Taiga starts, but Aomine shakes his head.

“He’s only doing all this because you asked him to. I peg him as the type to pass me off as the village’s problem, if he thought he could manage it.”

Taiga waits for the surge of defensiveness in the name of his father’s honor, but it doesn’t come. He can’t say for sure if Aomine is right or not, but either way, he isn’t angry when he’d expected to be, and that’s unusual.

“I dunno,” he says, because that’s the truth. “You’re hurt, and you were in trouble. It was the right thing to do.”

“That’s the whole reason?”

Though he will never see him in it, Taiga can’t help thinking that Aomine’s gaze is like the sea. Deep and imperious, dragging him in like the tide. He doesn’t say anything, but he does lift his head and sit back in an attempt to break the pull.

“I don’t think it is,” Aomine concludes, but he lets him get away with it this time. 

.

.

As promised, Taiga’s father fills the jacuzzi first thing in the morning, and then heads into town. It takes him over an hour to travel there and back, but it seems like his search for a good dechlorinator is successful, because it isn’t long after that he’s calling for Taiga to help him move Aomine.

“Fucking finally,” Aomine says, allowing them both to manhandle him out of the bathtub and carry him outside. It’s just as much of an awkward, difficult process as it had been to get him _in_ the tub in the first place; he’s a lot heavier than he looks, and really slippery, and he doesn’t seem to have much control of his tail while he’s airborne, whacking Taiga often with the wet, slimy length of it.

Or maybe he just does that on purpose.

It’s not easy to maneuver him into the spa pool either, but once they’ve got him positioned tail-first over the gently moving water, he plunges right into it with a grateful sigh, submerging himself completely.

At its deepest point, the water in the pool would about reach Taiga’s chest if he were standing, and it’s wide enough across to even swim a few strokes, which Aomine does, his tail moving against the flow enough to propel him from one end to the other.

His wet head bobs back up on the other side, and he seems to relax and just let the water carry him in a slow, lopsided circle back toward Taiga and his father.

“Fuck, that feels so much better,” he says earnestly, shaking water from the ends of his hair. And it could be the natural sunlight, in contrast to the artificial bulbs in the bathroom, or it could be a testament to his statement, but Taiga thinks his fins and scales actually look more intense than they did before, shimmering with brilliant shades of blue, the rays of his tail showing up practically turquoise against their indigo backdrop. Even his gills seem to have a brighter, healthier cast around them, as he stretches his arms up over his head. Taiga has to wonder if a minute and a half in his new environment could really make that much of a change. 

“Think you’ll be alright in there for a couple of days?” Taiga’s dad asks, bending down as if to inspect his handiwork. Taiga squats down beside him and rests his elbows on his knees, while Aomine does lazy laps in the crystal clear water.

“Yeah, I should be good,” Aomine says over his shoulder, seeming to still be relishing in his newfound space and mobility. 

“Good. Let me know if the current is too much or you want the temperature changed, and keep monitoring your wound to make sure it doesn’t tear, or become inflamed. Don’t overexert yourself.”

Taiga recognizes that last remark as his father excusing himself, and can’t help thinking back to Aomine’s commentary from the night before, but he doesn’t say anything as he watches him climb down onto the patio and head back to the house without another word.

Hesitantly, he sits down on the deck of the spa, and lets his bare feet dip into the cool water. It is rather pleasant, refreshing, though he’s used to it being much warmer. He can’t imagine what it must be like for Aomine, going from the stale, stagnant water of the cramped bathtub to suddenly being able to breathe and move freely again, what a relief it must be, but he’s pretty content to sit there and watch him splash and whoop like a kid at the beach, as long as he cares to let him.

.

.

Taiga brings Aomine his dinner just before the sun starts to go down. The marsh is cast in a soft golden glow in the last of the dying light, and the mountains in the distance have started to melt back into the sky, a haze of mist blurring out all their finer details. A chill breeze is ruffling the surface of the lake, but Aomine doesn’t seem to mind, coming to a stop at Taiga’s feet and propping his arms on the edge of the pool. 

It’s been about two days since he was transferred from the tub to the larger jacuzzi pool, and he seems to have settled right in. His only complaint now is continued boredom, which Taiga does his best to help alleviate, talking to him, asking about his life outside the marshes and answering questions about his own, sometimes bringing a magazine or a game to show him. Mostly, though, he just comes to watch him swim graceful loops around the perimeter of the pool; his tail is getting stronger every day, and even the tears in his fins are starting to fill in, pale and translucent around the edges as they knit back together. He shouldn’t have to remain confined here for too much longer, according to Taiga’s dad… though Taiga can’t seem to shake a strange feeling of regret whenever that thought takes hold. 

They eat together, looking out at the lake, still pushing past its banks and creeping up to the steps of the patio. The water in the spa feels warm in contrast to the cool evening air, so Taiga lets his legs dangle in it up to the shins. He figures his swim trunks are rather appropriate attire for a poolside meal, and it occurs to him suddenly how much more time he’s spent outdoors this summer than he had intended to. 

“What are these?” Aomine asks at length, poking at the crisp, buttery discs on his plate, having already put quite a few of them into his mouth.

“Seared scallops,” Taiga says. “I just made them.”

“You’re shitting me,” Aomine says accusingly, after scarfing down another scallop with enthusiasm. “There’s no way you made these.”

“I did too,” Taiga argues, setting his own plate aside. “I asked Dad to get them fresh when he went into town.”

“How the hell,” Aomine says, “do you make fucking scallops taste this good?”

“Well, it’s all about how you prepare them, if you --”

“That was rhetorical,” Aomine interrupts, holding up a hand to stop him. “I don’t actually need to know how to cook scallops, thanks.”

Taiga noticed, when he raised his arm, that his gill slits appear to be flushed with color, even in the weak sunlight. The skin around them has turned a delicate shade of violet, the scales along his back a rich, dazzling blue. He thinks there might even be subtle hints of red and purple in the crannies of his fins that there definitely weren’t before.

“Hey, I’ve been meaning to ask…” he prompts, swinging his legs in the water below. “Are you… have you been… changing colors, recently?”

To his surprise, Aomine looks embarrassed by the question, toying with the last scallop on his plate before placing it on his tongue.

“These are my spawning colors,” he says grudgingly once he swallows, his eyes fixed on the other side of the pool.

“Spawning?” Taiga echoes, leaning in to try and better read his expression. His eyebrows are drawn close together, and he’s not blushing, but then, Taiga’s not sure if he even can. His fins certainly seem to be.

“Yeah,” Aomine nods, clearing his throat, though he still seems reluctant to answer. “Happens when uh -- _my kind_ find, um… a potential mate.”

The last part is little more than a mumble, but Taiga still catches it, and feels his mouth fall open of its own accord, though he hasn’t got a clue what he’s supposed to say. Because there isn’t anyone else he can possibly mean, is there?

“You… you think I’m --?” he stammers out, but Aomine is quick to interrupt.

“I can’t exactly help it,” he bursts out angrily. “It’s just something that happens, okay? And it doesn’t mean you have to -- I just… Forget it.”

With that, he shoves away from Taiga and retreats, as quick as his injury will allow.

“Hey, wait a second --!” Taiga blurts, stretching out his hand, but he’s already on the other end of the pool, his back turned, his tail swaying behind him in the current. Closing his fist, Taiga sits back on the deck and looks at him; the shaft of amber light playing off the gorgeous, iridescent sheen of his body, catching on the curve of the cheek turned stubbornly away from him.

Sighing harshly, he gets to his feet and strips out of his shirt, tossing it behind him just before he jumps in the water. There’s no way Aomine can miss the massive splash as he breaks the surface, and by the time he gets to the other side, he’s staring at Taiga, open-mouthed, his expression one of outrage.

“That’s not fair,” he says, crossing his arms above his gills. Taiga just shakes his soaking bangs out of his eyes and shrugs.

Aomine glares at him a little longer, his tail twitching through the water like an angry cat’s, before he seems to give it up as a bad job and hangs his head with a sigh.

“What…” he begins, sounding awkward and uncertain as he watches the water lapping at their chests. “What do _your_ people do when… when you fancy someone?”

Taiga is surprised, but tries not to show it as he considers the shockingly honest, to-the-point question.

“Well,” he says slowly, shifting his feet on the bottom of the pool, “I think… telling them is a pretty good start.”

Aomine lifts his head to look at him again, the anger gone from his face to be replaced by curiosity. Maybe a glimmer of hope. All of which is quickly suppressed as he _tsks_ with annoyance.

“So much of your culture is fucking _verbal_ , it’s really frustrating,” he says. “I’ve been sending signals your way for _days,_ and all I had to do was --?”

He stops, because Taiga is suddenly right in front of him, only a few centimeters away, looking straight into his depthless eyes and gradually relinquishing himself to their pull. He doesn’t have a concrete plan, exactly, but he thinks Aomine must be able to guess a few of his thoughts just by looking at him. 

He spares one for the possibility of his father deciding to come out on the patio this late in the day, but reasons that even if he did, he probably wouldn’t be able to see much, and the sliding door should give them enough advanced warning even over the hum of the jets. 

“Um… so… another thing we might do is…” he says haltingly, lifting his hands out of the water to guide Aomine closer, checking his willingness all the while. His eyes have gone wider than Taiga has ever seen them, no longer shielded by their see-through lids, but he doesn’t protest, even as Taiga turns his head to the side and slowly brings their lips together.

Aomine’s are cooler than his, and maybe a little firmer, but after a few seconds of confused inaction, they seem to catch on to the idea, and push back against Taiga’s with the kind of eagerness that can only come from the desire to understand and participate. Taiga shows him, opening his mouth and pressing at the seam of Aomine’s with his tongue. Aomine parts his lips hesitantly, and Taiga dips between them for a moment, stroking over his teeth and palate once before he withdraws.

“What,” says Aomine, breathing unevenly through his mouth; beneath the water his gills are also working hard, “was _that?”_

“That was a kiss,” Taiga explains, thinking with the still-functional half of his brain that he might also be rather breathless. The corner of his mouth kicks up a little in amusement, “I guess it’s… a thing people do with their potential mates?”

“Can we do it again?” Aomine asks, barely waiting for him to finish speaking. He’s wetting his lips nervously, and his eyes haven’t strayed from Taiga’s for a single second. There’s a hunger in them now, something dark and wild and burning with curious need.

“...Okay,” Taiga says, bringing his hands up to cup Aomine’s jaw, tilting his head just a little before he dives back in. 

To his surprise, Aomine pushes into him this time, slick scales grazing his skin as he grips Taiga’s bare shoulders to steady himself. A slap of water hits Taiga’s chest, and Aomine’s mouth tastes like salt and scallops, his hair coarse and damp between Taiga’s grasping fingers.

Aomine’s hands move down, stroking keenly over Taiga’s chest, and stall in place underwater when they brush against his nipples.

“I’ve never understood the point of these things,” he says, breaking away order to do so. 

Taiga laughs at him before he even thinks about it, and then gasps when Aomine’s fingers turn to lightly pinching, rolling the stiffening buds in his grasp with interest.

“You’re sensitive here, huh?” he murmurs, squeezing the point of Taiga’s left nipple between his finger and thumb, looking up from his chest to meet his gaze. In the softly moving water, Taiga can feel his swim trunks pulling tight, a surge of carnal interest shooting from his chest down into his groin, and watching the reflexive flare and curl of Aomine’s color-flooded fins against the current is doing nothing to cool him off.

“Fuck,” he says, wondering how the hell he’s stared at him this long without realizing he’s so beautiful. “Can I touch you too?”

Aomine pauses, and one of his hands leaves Taiga’s chest to grasp his wrist.

“Sure,” he says, guiding it to his side below his gill. “Here.” 

Taiga runs his thumb over the indicated area, fascinated that his scales aren’t rough at all, in fact they feel almost polished smooth, slippery to the touch, and he can just detect a whisper of water across his knuckles as it’s expelled from Aomine’s gills. As he slides his hand a little higher, a shiver runs through Aomine’s body, and his breath starts getting shaky.

“...What were you saying about being sensitive?” he asks, tracing the pads of his fingers with the barest contact over the fluttering slit. 

Though Aomine bites it off quick, Taiga definitely hears him start to moan softly, his tail moving in a restless slash through the water as he grips Taiga’s upper arms. Oh yeah, he’s definitely onto something there. Bending low, he turns his head to press his mouth to the side of Aomine’s neck, his thumb rubbing little circles around the edge of the tender opening, following the curve of it around to Aomine’s shoulder blade. 

“Is this okay?” he asks against the wet skin of Aomine’s collarbone, his free hand carefully locating the gill on his other side. 

“Yeah,” Aomine grunts, all but squirming in Taiga’s grasp as he starts stroking on both sides, his fingers clenching down around Taiga’s biceps as he pants, hard and open-mouthed, as if the stimulation to his gills is making it difficult to use them for their intended purpose. “Hey, can you — can we — kiss again?”

“Are you sure?” Taiga asks, without stilling his hands. “You look like you’re having some trouble breathing there.”

“Please?” Aomine adds, like an afterthought, and the roughness of his voice kind of does Taiga in. But rather than kiss Aomine’s mouth, this time he dips his head below the surface and touches his lips to the sensitive ridge of one of his gills, runs his tongue along it, applies suction to the skin as much as he can without swallowing water. 

Aomine shudders against him, like he’s startled, his hands shifting to grab his hair, but every move Taiga is making seems to draw a new sound from him, and by the time he has to come back up for air, he’s not entirely certain that Aomine is going to let him. 

He does, releasing Taiga’s head as soon as he starts to lift it, and as he slicks back his wet hair and catches his breath, Taiga takes a moment to just look at him. It’s hard to say he looks wrecked in the traditional sense, but he’s still gasping irregularly, his eyes unfocused, his tail tossing back and forth in the water like he can’t keep it still. And just in front of the small fin on his underside, Taiga notices something else. Something peeking out of a slit in the lower part of his belly. 

“...I’m gonna hazard a guess and say you liked that,” he says, and he’s going for teasing, but it comes out way too strained as he angles his chin at the evidence — unless he’s mistaken, and he doesn’t think he is — of Aomine’s enjoyment. 

“No shit,” Aomine pants. “I knew... they could be sensitive, but _damn…”_

“You mean no one’s ever done anything like that before?”

“Nope,” Aomine shakes his head, nearly tipping himself over sideways with the motion. 

“You still okay?” Taiga feels like he should probably check, observing his labored breathing and kind of hazy eyes. 

“Uh-huh… one second,” Aomine says, and dunks himself fully underwater for about a second or two. Then he pops back up with a relieved sigh, seeming to draw breath easier and with more regularity, like he’s gotten his head on straight. 

Taiga’s not sure if it’s a “bucket of cold water” type of deal, or just a matter of staying wet, but he’s not going to ask. And he can’t seem to stop glancing at the length of tapered flesh slowly emerging from Aomine’s vent, which his actions did nothing to subdue.

“You gonna finish what you started, or just look at it?” Aomine asks plainly, fanning his tail out and quirking an eyebrow like it’s an invitation. Or a challenge. 

Taiga has never been good at refusing either. 

“Here, back up a bit,” he says, crowding Aomine closer to the side of the pool. There’s a raised bench under the water there, and sitting on it positions Taiga a little lower, so that the water covers his shoulders. Aomine faces him, and grabs the edge of the pool on either side of Taiga’s head, bringing them almost nose to nose.

From this angle, with Aomine floating just slightly above him, Taiga can reach straight out and touch his stomach, so he does, smoothing his hands along the glossy skin and scales that lead toward his tail. Aomine seems to have another goal in mind, however, and before Taiga reaches the slit in his belly, he’s bringing their mouths back together, pushing between Taiga’s lips with an inquisitive tongue. The kiss is unsurprisingly wet, but with Aomine taking the lead, it is surprising how fast it gets hot, considering his lower body temperature. Within a minute Taiga is shifting in place on the bench, his swim trunks clinging uncomfortably to his skin as he grips the back of Aomine’s neck and reciprocates the pressure. With his other hand, he starts pushing on the waistband of his trunks, wiggling them down past his hips to get some relief.

Aomine kisses, like everything else, with his eyes open, so it’s easy for Taiga to spot the curious downward glance in the moment before he disconnects their lips.

“What do you usually do?” he rasps, as he draws himself closer, the slits of his gills almost touching Taiga’s chest. Taiga slides one of his hands down to graze over them, watching the rhythm of Aomine’s tail stutter, and then, as an answer, brings his other hand underneath him and strokes along the swollen, gently curving shaft pushing out of his vent. Like every part of Aomine’s body, it feels slick; his fingers glide easily from the base to the pointed tip, and the gasp it draws from Aomine is extremely satisfying.

“Oh, shit,” he says, his tail swaying slower to allow Taiga better access as he supports himself on the rim of the pool. Taiga takes him up on it, closing his hand around the length of him, caressing him more firmly and hearing him moan low in his throat. 

As he gets comfortable, he gradually ups the pace, jerking Aomine like he would himself, though he’s not sure with the difference in anatomy if Aomine will be responsive to the same treatment. He certainly seems to be, if his expression and the little hitches in his breath are any indication, the upper flap of his gill slit quivering under Taiga’s stroking fingers. Taiga leans his head forward and kisses him, hard and wet but short enough to let him breathe, and then Aomine grits his teeth and starts moving with the rhythm of Taiga’s hand. 

He doesn’t so much thrust into Taiga’s fist as snug himself into it, using his tail to push his body forward and grind against him with the lateral movement he’s more capable of, the muscles of his arms tensing to keep him right there, right in that sweet spot. He’s breathing fast now, gulping air through his mouth that’s quickly pushed out through his gills, and Taiga can see the strain of his tail, flaring like an underwater sail as it moves.

“Yeah?” he asks, watching Aomine’s face as he adjusts his hold on him, wringing his hand all the way down. Aomine just groans, wordless, and his whole body goes rigid right before a cloud of whitish fluid spills from him into the water. 

After a moment, his arms sag against the rim of the pool and he goes loose, his tail stirring back to life as he comes down from his release. His breath is still ragged, but it starts to even out over time as well. 

“So… spawning, huh?” Taiga says, breaking the quiet.

Aomine looks at him with a strange expression, and then sighs heavily and sinks down into the pool, “Shut up.”

“You know, I gotta say, I wasn’t expecting that when my dad and I brought you in from the lake.”

“Shut the _hell_ up,” Aomine says emphatically, scrubbing his hands over his face before dropping them into the water. “Do you want me to get you off too, or not?”

“Huh?”

“‘Cause if you’re gonna keep making fun of me and talking about your dad, you can forget it.”

It’s a little difficult to tell when his skin doesn’t flush, but finally it hits Taiga that the sulky tone and the twist of emotion on his face are from embarrassment.

“Okay… so what would you do if I shut up right now?”

Aomine keeps on frowning at him for a couple more seconds, but he seems to become more agreeable as, true to his word, Taiga doesn’t say anything else.

“Well, I was just thinking,” he says, his gaze darting down to the bench where Taiga is sitting, “about how, unlike you, I can breathe underwater.”

“Oh?” Taiga blinks, thinking he might be starting to catch on as, without another word, Aomine immerses himself completely, his head disappearing below the surface just before he settles between Taiga’s knees. _Oh..._

It’s almost funny, Taiga thinks, how quickly the thought alone excites him, his cock returning to full hardness before it had even really started to flag. Aomine’s hands come to rest on top of Taiga’s thighs, his tail waving leisurely through the water behind him, his shoulders and the slope of his dorsal fin coming just within reach as he lowers his head. 

Taiga grips the former, his hands sliding down the scales on Aomine’s back, as he feels lips brush against his stomach, followed by a swirling tongue, the barest scrape of teeth beside his navel. Aomine travels down slowly, kissing his waist and hips as his fingers curl in the material of his swim trunks, easing them past his knees and ankles and finally discarding them. And Taiga doesn’t have time to voice a protest -- imagining them being sucked into the jacuzzi filter and lost forever -- before Aomine shifts and places his mouth on the tip of his cock, rolling his lips around it and lapping it with his tongue. 

“Fuck…” Taiga grunts, his head falling back against the rim of the pool as Aomine starts sucking firmly, sliding him deeper into his mouth. Under the water, Taiga’s hands slip on his scales, unable to find purchase, until one of them grasps the fringe of his dorsal fin. He doesn’t seem to mind, plunging his head down to take Taiga’s cock into his throat, the suction deep and wet as water rushes past the throbbing flesh on the way to his gills. His hands are holding Taiga’s hips down, as if he might try to move them, but he must either not have a gag reflex or be very good at suppressing it, because he doesn’t seem worried about choking as he swallows Taiga’s cock to the root.

Taiga’s not going to last long, and he knows it; he’s been moaning almost non-stop since Aomine sank all the way down on him, his eyes squeezing shut and his hands holding on tight, one on the silky wet ridge of Aomine’s dorsal, the other buried in his hair. He’s too worked up, and he thinks Aomine can sense it too, because although Taiga can’t hear his hum of satisfaction under the water, he can still feel it vibrate against his dick.

Aomine’s throat ripples and flexes around him, seeming to pull him in even deeper, though the bridge of his nose is touching Taiga’s stomach and there isn’t any further he can go, and Taiga’s spine is tensing, his balls are clenching, and all of a sudden he’s tipping over the edge.

He comes down Aomine’s throat with a drawn-out groan, his hips lifting up off the bench, and Aomine eagerly swallows it down, creating a seal with his mouth around Taiga’s cock before slowly pulling back and releasing him. Then he swishes his tail once and rejoins him above the surface.

Taiga doesn’t think or wait for him to speak, just pulls him over and crashes their mouths together, tasting the bitter salt on his tongue and hearing his sound of surprise melt into a muffled moan. His hands come up to wrap around Taiga’s shoulders, and he kisses back, only breaking away to allow both of them to grab a much-needed breath.

“You were pretty loud,” he says smugly, as he settles beside Taiga at the edge of the pool, folding his arms on the rim and sweeping his tail back and forth.

“You could hear me?” Taiga blinks, taken aback.

Aomine nods, resting his cheek on his arm to look at him. 

“Sound travels fast underwater, genius.”

“Oh.” Too worn out to be chagrined, Taiga just leans against his scaly shoulder and closes his eyes, turning his head to press a kiss to it when Aomine doesn’t move. 

“Hey, don’t fall asleep,” Aomine says, sounding pretty worn out himself. “You might drown.”

Taiga laughs softly, “You wouldn’t let me drown.”

“Yes I would.”

He sounds dead serious, but Taiga just laughs again, and sits up straight. 

“I should probably get out soon anyway, I’m starting to wrinkle.”

Showing his prune-like fingers to Aomine as proof, he pushes off of the bench and gets to his feet. Aomine turns at his cue, and follows him to the middle of the pool, his fins flowing effortlessly through the water. 

“If you lost my swim trunks, though…” Taiga says, “ _you_ get to explain if my dad catches me sneaking in without them.”

.

.

“Looks like your tail’s just about finished healing,” Taiga’s father says, examining the thin split in Aomine’s scales that has become almost invisible from a distance. “You should be good to go.”

It’s good news, of course, but Taiga still feels a bitter sink of disappointment as Aomine nods and extricates his tail from his grasp. It’s far brighter than it had been when he first arrived, shot through with color that has only bloomed more vividly over time, a visual cue that Taiga now recognizes the significance of. And he doesn’t think he’s imagining the hesitation weighing on Aomine’s gaze either. 

“Are you sure?” he asks, stretching out the limb and spreading each one of his fins in turn. 

“Pretty sure,” Taiga’s father says. “It’s not bleeding or even irritated anymore, and you seem to have your full range of motion back, unless I’m mistaken.”

Aomine bends his tail to one side, then the other, then twists it and gives a powerful slap to the surface of the water, raising a sharp splash. 

“Seems like it,” he agrees. 

“Besides,” Taiga’s father continues, “the lake has already gone down quite a bit, and the channels are starting to dry up. If you wait too long, you may not be able to make your exit.”

Aomine glances at Taiga sidelong, just fleetingly, and sighs. 

“Alright,” he says. “Put me back in.”

“Let me just grab my gloves,” Taiga’s father says, getting to his feet. 

Once he’s out of earshot and they’re on their own, Taiga turns back to Aomine. 

“He still won’t touch me without gloves,” Aomine remarks flatly, rolling onto his side in the pool, the midday sun reflecting off his skin and scales so that he almost glows in the light. 

“It’s because you’re too slimy,” Taiga says, reaching out to splash him with a handful of water.

“Yeah, I’m slimy, and _proud_ of it,” Aomine says, putting a hand to his chest importantly, just above the violet crescents of his gills. 

Taiga laughs, settling on the spa deck with one knee bent in front of him. He really wants to jump in the water and kiss Aomine one more time while he has the chance, but he doesn’t know how long his dad will take getting his gloves from inside the house. 

“Where will you go?” he asks instead, lacing his fingers around the shin of his bent leg and resting his chin on his knee. 

“Probably somewhere with nice, clear running water,” Aomine says, watching his own tail streaming through the current from the jets. “I think I’ve had enough of marshes for awhile.”

“Do you think we’ll see each other again?”

Aomine looks up at that, his mouth slightly ajar, like he doesn’t know what to say. 

“...Maybe,” he decides on at length, without taking his eyes from Taiga’s. “But, I mean, you’re leaving here pretty soon too, aren’t you?”

“I’ve still got about a week,” Taiga points out, shrugging. “And there’s always next summer. You know where to find me.”

“Assuming I can get back once the channels run dry,” Aomine says doubtfully. 

“Then I’ll come and visit you,” Taiga says. “Whichever body of water is nearest.”

He cracks a smirk, and is pleased to see that after a moment of pause, Aomine returns it. 

“Alright, fine,” he says, rolling his eyes. “If you’re that set on it, I guess next time I can show you where I come from.”

Taiga’s grin widens, and doesn’t lose steam even as he hears the door to the house slide shut somewhere behind him. 

“I’d like that.”

Aomine gazes up at him, his clear blue eyes unobstructed by even transparent lids, his vibrant tail swaying as if in deep thought. 

He doesn’t say _‘me too,’_ but he does smile and say, “Bring your swim trunks.”

  
  


FIN 

**Author's Note:**

> (...geddit)
> 
> Word to the wise, don't let the massive fish nerd take a crack at the merman AU, or else you'll end up with 9k words of this scaly fishy nonsense.
> 
> Yes, the marsh house setting was loosely inspired by When Marnie Was There. No, the human/fish person romance was not inspired by The Shape of Water, and yes, I do know how gills and gonopodiums are supposed to work, but I bent the rules a bit where necessary. Scientific accuracy isn't always that sexy.
> 
> Comments, as always, are greatly appreciated. I dunno how many of y'all will appreciate this weird, niche fic, but it was still damn fun to write. Also, I've got [concept art](https://theshinsun.tumblr.com/post/611094220434030592/get-fuckin-ready), and there's definitely a possibility of more developed drawings in the future, and/or other content set in this universe. 
> 
> Thanks for reading!


End file.
